This invention relates to silver halide color photographic materials. More particularly, it relates to color photographic materials which contain yellow dye-forming couplers in combination with certain non-imaging compounds which give rise to images which have high stability towards fading by light.
In a silver halide photographic element, a color image is formed when the element is exposed to light and then subjected to color development with a primary aromatic amine developer. Color development results in imagewise reduction of silver halide and production of oxidized developer. Oxidized developer reacts with one or more incorporated dye-forming couplers to form an imagewise distribution of dye.
In any polychromatic chromogenic photographic material it is desirable that the dyes so formed should have certain properties. For instance, the dyes should be bright in color with very little secondary absorption so that good color reproducibility is obtained. For yellow dyes in particular, color purity is enhanced by ensuring that the absorption maximum of the dye is well separated from that of the magenta dye and hence, yellow dyes that absorb at shorter wavelengths are advantageous. Acetanilide-based yellow dye-forming couplers have been found to provide desirable hues. The dyes that are formed by any color coupler during processing have a tendency to fade over times as a result of exposure to light, heat, humidity and oxygen resulting in a deterioration of the original recorded image. It is therefore highly desirable that the yellow dyes should be resistant towards fading by heat, humidity and light.
Acetanilide-based yellow dye-forming couplers of the general structures described in this invention are well known in the photographic art. Techniques are known in the art for providing resistance to light fade of such photographic yellow dyes. Compounds which have been disclosed as light stabilizers for yellow image dyes include substituted phenolic and blocked phenolic compounds including; heterocyclic phosphorous materials (U.S. Pat. No. 4,749,645), phenolic thiane derivatives (EP 0 310 551), substituted and blocked bisphenols (UK 1,267,287, U.S. Pat. No. 4,782,011, DE 4,307,439, DE 4,307,439, DE 4,320,828, EP 0 508 398, EP 0 538 862, U.S. Pat. Nos. 5,294,530, 5,426,021, 5,441,855, 5,441,861, 5,466,569, 5,891,613, WO 91/008,515, U.S. Pat. Nos. 5,567,578, 5,284,742, 5,091,294, EP 0 310 552, U.S. Pat. No. 5,935,773). In addition, yellow dyes may also be stabilized against fading by light with the use of thiomorpholine dioxide compounds as described in copending, commonly assigned U.S. Ser. No. 09/483,396 filed Jan. 14, 2000, the disclosure of which is incorporated by reference herein. However, it is desirable to improve on the light stabilization of yellow dyes beyond that afforded with use of the above stabilizers.
Acetanilide-based yellow dyes can also be stabilized against light fade with the use of some polymeric stabilizers. Polymeric compounds which have been disclosed as light stabilizers for yellow image dyes include, for example, those described in U.S. Pat. Nos. 4,857,449; 5,001,045; 5,047,314; 5,055,386; 5,200,304; 5,242,788; 5,294,527, 5,558,980, 5,594,047, and 5,981,159. Various techniques have been disclosed for preparing photographic dispersions of yellow dye-forming couplers and latex polymers, e.g., as described in U.S. Pat. Nos. 5,594,047 and 5,558,980. However, dispersions of yellow dye-forming couplers and polymeric addenda coated in a photographic element, whether it be the use of polymer latex particles or low molecular weight organic solvent soluble polymers, have disadvantages. With respect to polymer latex particles, they can be difficult to clean in large-scale manufacturing. In photographic elements, density increases after thermal treatments are also caused by the use of high levels of latex polymers. With respect to the solvent soluble polymers, they can be difficult to dissolve in coupler dispersions without the use of a low-boiling water-immiscible solvent, such as ethyl acetate. This is environmentally unfavorable, and often requires the additional step of removing the solvent before it can be coated in large-scale manufacture of photographic materials.
Typically, the yellow dye-forming color coupler and polymeric light stabilizer are dispersed in gelatin or other colloidal binder. In the dry state the gelatin is hard and can easily transmit applied stress to the silver halide grains. This can result in an unwanted xe2x80x9cfoggingxe2x80x9d of the emulsion, meaning that a latent image site is formed due to the transmitted stress and not due to exposure with light. This is typically referred to as xe2x80x9cpressure fogxe2x80x9d. Techniques are known in the art to reduced pressure sensitivity by addition of dispersions of organic solvents to photographic elements (U.S. Pat. Nos. 4,840,881 and 4,499,179). However, these organic solvents are not themselves capable of providing light stability, most often degrading light stability, and can be used at such high levels that other problems are encountered such as delamination between adjacent layers in the photographic element. Similarly, prior art discloses the use of low glass transition temperature polymer latex into coated photographic elements to reduce pressure sensitivity (U.S. Pat. Nos. 3,576,628 and 4,822,727). Additional art discloses the use of gelatin-grafted and case-hardened gelatin-grafted soft latex polymer particles in combination with certain sugar surfactants (U.S. Pat. Nos. 5,066,572, 5,426,020 and 5,393,650). However, these particles do not offer any protection from fading of yellow image dyes due to light. Some latex polymers can be formulated to provide both light stability and pressure fog protection, such as described in U.S. Pat. No. 5,981,159. These latex polymers have the disadvantages mentioned previously.
Yet another method of stabilizing yellow dyes to fading by light is to disperse the yellow dye forming couplers in solid coupler solvents, such as alkyl alcohols or dialkyl or diaryl phosphates, according to U.S. Pat. No. 5,405,736. Such approaches can be disadvantaged in that the solid coupler solvent may precipitate or may cause precipitation of the yellow dye forming coupler or other solid materials during storage of the dispersion, which could lead to defects in the manufacture of a photographic element. Therefore, it is desirable to provide alternative methods of providing stabilization of yellow dyes to the fading of light without the inherent difficulties associated with known techniques of light stabilization.
An objective of this invention is to provide photographic elements which exhibit exceptional yellow dye light stability, and which retain desirable properties derived from the use of acetanilide based yellow dye-forming couplers. A further objective of the invention is to provide reduced pressure sensitivity for photographic elements comprising acetanilide based yellow dye-forming couplers.
In accordance with one embodiment of the invention, a photographic element is disclosed comprising a silver halide emulsion layer having associated therewith an acetanilide based yellow dye forming coupler and a compound of the following Formula I: 
wherein R1, R2 and R3 are each independently aromatic, cyclic, linear, or branched chained hydrocarbon groups. We have found that the objectives of the invention can be achieved with acetanilide-based couplers through the use of urethane compounds of Formula I as stabilizing addenda, particularly when used in combination with known substituted phenolic and/or thiomorpholine dioxide stabilizers. In addition to stabilizing properties, compounds of Formula I have organic solvent properties, and accordingly may be advantageously used partly or totally in place of conventional high boiling permanent and/or auxiliary organic coupler solvents to disperse the acetanilide-based couplers. Unexpected and substantial improvements in the light stability of the image dyes can be obtained, and, in accordance with preferred embodiments of the invention, the presence of the urethane compound does not degrade the pressure sensitivity of the resulting photographic element where the melting point of the compound is less than 110xc2x0 C. Accordingly, photographic elements of the present invention upon exposure and photographic processing exhibit good activity and yield yellow dye images that have low fading when exposed to light and are less susceptible to pressure induced sensitometric defects.
The photographic elements of this invention can be chromogenic black and white elements (for example, using magenta and cyan dye forming couplers in combination with yellow dye forming couplers), single color elements or multicolor elements. In addition to a yellow dye image forming layer, the photographic elements in accordance with preferred embodiments of the invention further comprise at least one cyan image forming layer and at least one magenta image forming layer. More particularly, multicolor photographic elements in accordance with preferred embodiments of the invention preferably comprise a support bearing light sensitive image dye forming layers sensitized to the blue (approx. 380-500 nm), green (approx. 500-600 nm), and red (approx. 600-760 nm) regions of the electromagnetic spectrum. In accordance with a preferred embodiment of the invention, the element comprises cyan, magenta and yellow dye forming silver halide emulsion hydrophilic colloid layer units sensitized to the red, green and blue regions of the spectrum. Each unit can comprise a single emulsion layer or multiple emulsion layers sensitive to a given region of the spectrum. The layers of the element, including the layers of the image forming units, can be arranged in various orders as known in the art. It is within the scope of this invention, however, for the light sensitive material to alternatively or additionally be sensitive to one or more regions of the electromagnetic spectrum outside the visible, such as the infrared region of the spectrum. In most color photographic systems, non-diffusing color-forming couplers are incorporated in the light-sensitive photographic emulsion layers so that during development, they are available in the emulsion layer to react with the color developing agent that is oxidized by silver halide image development. When the dye image formed is to be used in situ, couplers are selected which form non-diffusing dyes. Color photographic systems can also be used to produce black-and-white images from non-diffusing couplers as described, e.g., by Edwards et al. in International Publication No. WO 93/012465.
Throughout this application a reference to any type of chemical xe2x80x9cgroupxe2x80x9d includes both the unsubstituted and substituted forms of the group described. Generally, unless otherwise specifically stated, substituent groups usable on molecules herein include any groups, whether substituted or unsubstituted, which do not destroy properties necessary for the photographic utility. It will also be understood throughout this application that reference to a compound of a particular general formula includes those compounds of other more specific formula which specific formula falls within the general formula definition. Examples of substituents on any of the mentioned groups can include known substituents, such as: halogen, for example, chloro, fluoro, bromo, iodo; alkoxy, particularly those with 1 to 6 carbon atoms (for example, methoxy, ethoxy); substituted or unsubstituted alkyl, particularly lower alkyl (for example, methyl, trifluoromethyl); alkenyl or thioalkyl (for example, methylthio or ethylthio), particularly either of those with 1 to 6 carbon atoms; substituted and unsubstituted aryl, particularly those having from 6 to 20 carbon atoms (for example, phenyl); and substituted or unsubstituted heteroaryl, particularly those having a 5 or 6-membered ring containing 1 to 3 heteroatoms selected from N, O, or S (for example, pyridyl, thienyl, furyl, pyrrolyl); and others known in the art. Alkyl substituents may specifically include xe2x80x9clower alkylxe2x80x9d, that is having from 1 to 6 carbon atoms, for example, methyl, ethyl, and the like. Further, with regard to any alkyl group, alkylene group or alkenyl group, it will be understood that these can be branched or unbranched and include ring structures.
Acetanilide-based yellow dye forming coupler compounds employed in the elements of the present invention are known compounds and can be prepared by techniques known to those skilled in the art. Individual yellow couplers may be used singly or in combinations. Couplers that form yellow dyes upon reaction with oxidized color developing agent and which are useful in elements of the invention are described, e.g., in such representative patents and publications as: U.S. Pat. Nos. 2,875,057; 2,407,210; 3,265,506; 2,298,443; 3,048,194; 3,447,928 and xe2x80x9cFarbkupplerxe2x80x94Eine Literature Ubersicht,xe2x80x9d published in Agfa Mitteilungen, Band III, pp. 112-126 (1961). Such couplers are typically open chain ketomethylene compounds. Also preferred are yellow couplers such as described in, for example, European Patent Application Nos. 482,552; 510,535; 524,540; 543,367; and U.S. Pat. No. 5,238,803.
Typical preferred acetanilide-based yellow couplers are represented by the following formulas: 
wherein R1, R2, Q1 and Q2 each represent a substituent; X is hydrogen or a coupling-off group; Y represents an aryl group or a heterocyclic group; Q3 represents an organic residue required to form a nitrogen-containing heterocyclic group together with the illustrated nitrogen atom; and Q4 represents nonmetallic atoms necessary to form a 3- to 5-membered hydrocarbon ring or a 3- to 5-membered heterocyclic ring which contains at least one hetero atom selected from N, O, S, and P in the ring. Preferred couplers are of YELLOW-1 and YELLOW-4 wherein Q1 and Q2 each represent an alkyl group, an aryl group, or a heterocyclic group, and R2 represents an aryl or alkyl group, including cycloalkyl and bridged cycloalkyl groups, and more preferably a tertiary alkyl group. Particularly preferred yellow couplers for use in elements of the invention are represented by YELLOW-4, wherein R2 represents a tertiary alkyl group and Y represents an aryl group, and X represents an aryloxy or N-heterocyclic coupling-off group. The elements of the invention are particularly useful in combination with yellow couplers of the above formulas wherein X represents a nitrogen-containing heterocyclic coupling-off group.
Representative yellow couplers which may be used in the elements of the invention include the following:
Urethane compounds of Formula I which are employed as light stabilizing compounds in photographic elements in combination with acetanilide based yellow dye formig couplers in accordance with the present invention may be prepared according to synthetic methods known in the art. Many diurethane compounds are commercially available and known in the open literature, for example, as emollients for use in cosmetics applications according to U.S. Pat. No. 5,972,324. Diurethane compounds are also known for use with ink-jet recording papers which show good printability with aqueous inks according to U.S. Pat. No. 4,960,638 and JP 02001360. Thermal recording materials are disclosed which contain a color former, color developer and urethane compound which show improved thermal sensitivity and prevention of undesired discoloration due to pressure according to JP 03256787. Urethane compounds are also disclosed as stabilizers for polymers, xe2x80x9cPolymer Degradation and Stabilityxe2x80x9d, volume 68, 2000, pp. 127-132. A general synthetic procedure involves reacting two molar equivalents of monohydric alcohols with a diisocyanate according to the following reaction in the presence of heat and a catalyst such as dibutyltin laurate: 
The diisocyanate can be chosen such that R1 is from the group of aromatic, cyclic, linear or branched chain hydrocarbon groups, preferably of from 1 to 30 carbon atoms, more preferably from 6 to 22 carbon atoms. Representative examples include: Isophorone diisocyanate, p-phenylene diisocyanate, toluene diisocyanate, 4,4xe2x80x2-methylenebis-(phenylisocyanate), 1,5-naphthalene diisocyanate, bitolyene diisocyanate, m-xylylene diisocyanate, m-tetramethyl xylylene diusocyanate, 1,6-diisocyanato-2,2,4,4-tetramethylhexane, trans-cylcohexane-1,4-diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, dicyclohexylmethane diisocyanate, methylene diisocyanate, ethylene diisocyanate; tri, tetra, penta, hexa, nona and decamethylene diisocyanates and the like.
R2 and R3 are aromatic, cyclic, linear or branched chain hydrocarbon groups, which may be the same or different, each preferably ranging from 1 to 22 carbon atoms, more preferably from 2 to 14 carbon atoms and most preferably from 4 to 10 carbon atoms, with linear, cyclic or branched chained alkyl groups being preferred. Representative examples of R2OH and R3OH include: Ethanol, propanol, iso-propanol, butanol, iso-butanol, pentanol, hexanol, ethylhexanol, nonanol, iso-nonanol, decanol, iso-decanol, undecanol, dodecanol, tridecanol, tetradecanol, myristyl alcohol, pentadecyl alcohol, cetyl alcohol, stearyl alcohol, arachidyl alcohol, behenyl alcohol, undecylenyl alcohol, palmitoleyl alcohol, oleyl alcohol, linoleyl alcohol, linolenyl alcohol, arachidonyl alcohol, erucyl alcohol, benzyl alcohol, cyclohexyl alcohol, phenoxyethanols and phenols. This list is non exhaustive and may also include numerous other monohydric alcohols having a terminal hydroxy group at the end of a linear, branched chain, cyclic, or aromatic hydrocarbon.
In accordance with preferred embodiments of the invention, the R1, R2 and R3 groups are preferably selected such that the melting point of the resulting compound is less than 110xc2x0 C. Addition of a compound of Formula I having a melting point of less than 110xc2x0 C. to photosensitive layer coatings advantageously provides improved pressure sensitivity performance in combination with improved light stability.
Representative compounds of Formula I which may be used in accordance with the present invention are as follows:
Typically, couplers and the stabilizers with which they are associated are dispersed in the same layer of the photographic element in a permanent high boiling organic compound known in the art as a coupler solvent, either alone or with auxiliary low boiling or water miscible solvents which are removed after dispersion formation. Permanent high boiling solvents have a boiling point sufficiently high, generally above 150xc2x0 C. at atmospheric pressure, such that they are not evaporated under normal dispersion making and photographic layer coating procedures. Alternatively, the couplers and stabilizers may be dispersed without permanent high boiling solvents using only auxiliary solvent or precipitation techniques as is known in the art. The compounds may be co-dispersed, or may be dispersed separately and then combined. Representative conventional coupler solvents include phthalic acid alkyl esters such as diundecyl phthalate, dibutyl phthalate, bis-2-ethylhexyl phthalate, and dioctyl phthalate, phosphoric acid esters such as tricresyl phosphate, diphenyl phosphate, tris-2-ethylhexyl phosphate, and tris-3,5,5-trimethylhexyl phosphate, citric acid esters such as tributyl acetylcitrate, tributylcitrate and trihexylcitrate, 2-(2-Butoxyethoxy)ethyl acetate, and 1,4-Cyclohexyldimethylene bis(2-ethylhexanoate), benzoic acid esters such as octyl benzoate, aliphatic amides such as N,N-diethyl lauramide, N,N-Diethyldodecanamide, N,N-Dibutyldodecanamide, mono and polyvalent alcohols such as oleyl alcohol and glycerin monooleate, and alkyl phenols such as p-dodecyl phenol and 2,4-di-t-butyl or 2,4-di-t-pentyl phenol. Commonly used coupler solvents are the phthalate esters, which can be used alone or in combination with one another or with other coupler solvents. Selection of the particular coupler solvent has been found to have an influence on the activity of the coupler as well as the hue and stability of the dye formed on coupling. In accordance with certain embodiments, the compounds of Formula I may be advantageously used to partly or totally replace conventional high boiling solvents in dispersing the acetanilide-based yellow dye-forming couplers in the photographic elements of the invention.
Typically the amount of compound I used will range from about 0.05 to about 4.0 moles per mole of coupler, preferably from about 0.1 to 2.5 moles per mole of coupler. The yellow coupler is typically coated in the element at a coverage of from 0.25 mmol/m2 to 2.0 mmol/m2, and preferably at a coverage of from 0.40 to 1.2 mmol/m2. When a conventional permanent coupler solvent is employed, it typically is present in an amount of 0.1 to 5.0 mg/mg coupler, and preferably in an amount of 0.25 to 2.0 mg/mg coupler.
To further enhance the stability of the yellow dyes formed in photographic elements in accordance with the invention, additional conventional stabilizing compounds may also be included. In accordance with a particularly preferred embodiment, the use of compounds of Formula I in combination with conventional substituted phenolic yellow dye stabilizers, and in particular substituted bisphenol based stabilizers, have been found to unexpectedly provide beneficial combinations of yellow formed dye light stability and good pressure sensitivity.
Substituted bisphenol light stabilizer compounds which may be used in accordance with preferred embodiments of the invention generally comprise bisphenol derivatives having two linked phenol rings wherein at least one of the phenol rings is substituted as described in the references cited above. Preferably, at least one of the phenolic hydroxy groups is also substituted with a blocking group. Such preferred blocked bisphenolic compounds are preferably of the following Formula II: 
wherein A represents an alkyl (e.g., methyl, ethyl, propyl or butyl), cycloalkyl (e.g., cyclohexyl), alkenyl, aryl (e.g., phenyl), acyl (e.g., acetyl or benzoyl), alkylsulfonyl or arylsulfonyl substituent group, X represents a single bond or a bivalent linking group (e.g., an alkylidene group such as methyline, butylidine, or 3,3,5-trimethylhexylidene, or a heteroatom such as oxygen, sulfur, selenium, or tellurium, or a sulfonyl or phosphinyl group), and each R independently represents one or more alkyl, alkenyl, cycloalkyl, or aryl substituent group, such as described for A above, or in combination with the benzene ring to which it is attached represents the atoms necessary to complete a fused ring system. Each A, X and R substituent or linking group may be further substituted or unsubstituted. Specific examples of such blocked bisphenolic compounds, along with synthesis techniques, are disclosed, e.g., in U.S. Pat. Nos. 4,782,011 and 5,426,021, the disclosures of which are incorporated herein by reference. Additional substituted phenolic stabilizers which may be advantageously used in combination with the invention include those described in U.S. Pat. Nos. 5,091,294, 5,284,742, 5,935,773 and EP 0 310 551 and EP 0 310 552. When used in combination with compounds of the Formula I, the substituted phenolic stabilizers may be used at similar concentrations. Preferably, the molar ratio of compound of Formula I to substituted phenolic light stabilizer compound is from 1:12 to 25:1. The compounds of Formula I may also be used in combination with thiomorpholine compounds as described in copending, commonly assigned U.S. Ser. No. 09/483,396 incorporated by reference above. While it is an advantage of the invention that improved light stability may obviate the need for polymeric latex materials as light stabilizers, they may also be incorporated if desired. Specifically, the polymer latex materials as described in U.S. Pat. No. 5,981,159 may be employed.
Image dye forming couplers that form cyan dyes upon reaction with oxidized color developing agents may be included in elements of the invention, such as are described in representative patents and publications such as: U.S. Pat. Nos. 2,367,531; 2,423,730; 2,474,293; 2,772,162; 2,895,826; 3,002,836; 3,034,892; 3,041,236; 4,883,746 and xe2x80x9cFarbkupplerxe2x80x94Eine Literature Ubersicht,xe2x80x9d published in Agfa Mitteilungen, Band III, pp. 156-175 (1961). Preferably such couplers are phenols and naphthols that form cyan dyes on reaction with oxidized color developing agent. Also preferable are the cyan couplers described in, for instance, European Patent Application Nos. 544,322; 556,700; 556,777; 565,096; 570,006; and 574,948.
Typical cyan couplers are represented by the following formulas: 
wherein R1 and R5 each represent a hydrogen or a substituent; R2 represents a substituent; R3 and R4 each represent an electron attractive group having a Hammett""s substituent constant "sgr"para of 0.2 or more and the sum of the "sgr"para values of R3 and R4 is 0.65 or more; R6 represents an electron attractive group having a Hammett""s substituent constant "sgr"para of 0.35 or more; X represents a hydrogen or a coupling-off group; Z1 represents nonmetallic atoms necessary for forming a nitrogen-containing, six-membered, heterocyclic ring which has at least one dissociative group. A dissociative group has an acidic proton, e.g. xe2x80x94Nxe2x80x94, xe2x80x94CH(R)xe2x80x94, etc., that preferably has a pKa value of from 3 to 12 in water. The values for Hammett""s substituent constants can be found or measured as is described in the literature. For example, see C. Hansch and A. J. Leo, J Med. Chem., 16, 1207 (1973); J Med. Chem., 20, 304 (1977); and J. A. Dean, Lange""s Handbook of Chemistry, 12th Ed. (1979) (McGraw-Hill).
More preferable are cyan couplers of the following formulas: 
wherein R7 represents a substituent (preferably a carbamoyl, ureido, or carbonamido group); R8 represents a substituent (preferably individually selected from halogen, alkyl, and carbonamido groups); R9 represents a ballast substituent; R10 represents a hydrogen or a substituent (preferably a carbonamido or sulphonamido group); X represents a hydrogen or a coupling-off group; and m is from 1-3. Couplers of the structure CYAN-7 are most preferable for use in elements of the invention.
Image dye forming couplers that form magenta dyes upon reaction with oxidized color developing agents may be included in elements of the invention, such as are described in representative patents and publications such as: U.S. Pat. Nos. 2,600,788; 2,369,489; 2,343,703; 2,311,082; 2,908,573; 3,062,653; 3,152,896; 3,519,429 and xe2x80x9cFarbkupplerxe2x80x94Eine Literature Ubersicht,xe2x80x9d published in Agfa Mitteilungen, Band III, pp. 126-156 (1961). Preferably such couplers are pyrazolones, pyrazolotriazoles, or pyrazolobenzimidazoles that form magenta dyes upon reaction with oxidized color developing agents. Especially preferred couplers are 1H-pyrazolo [5,1-c]-1,2,4-triazole and 1H-pyrazolo [1,5-b]-1,2,4-triazole. Examples of 1H-pyrazolo [5,1-c]-1,2,4-triazole couplers are described in U.K. Patent Nos. 1,247,493; 1,252,418; 1,398,979; U.S. Pat. Nos. 4,443,536; 4,514,490; 4,540,654; 4,590,153; 4,665,015; 4,822,730; 4,945,034; 5,017,465; and 5,023,170. Examples of 1H-pyrazolo [1,5-b]-1,2,4-triazoles can be found in European Patent Applications 176,804; 177,765; U.S. Pat. Nos. 4,659,652; 5,066,575; and 5,250,400.
Typical pyrazoloazole and pyrazolone couplers are represented by the following formulas: 
wherein Ra and Rb independently represent H or a substituent; Rc is a substituent (preferably an aryl group); Rd is a substituent (preferably an anilino, carbonamido, ureido, carbamoyl, alkoxy, aryloxycarbonyl, alkoxycarbonyl, or N-heterocyclic group); X is hydrogen or a coupling-off group; and Za, Zb, and Zc are independently a substituted methine group, xe2x95x90Nxe2x80x94, xe2x95x90Cxe2x80x94, or xe2x80x94NHxe2x80x94, provided that one of either the Zaxe2x80x94Zb bond or the Zbxe2x80x94Zc bond is a double bond and the other is a single bond, and when the Zbxe2x80x94Zc bond is a carbon-carbon double bond, it may form part of an aromatic ring, and at least one of Za, Zb, and Zc represents a methine group connected to the group Rb.
To obtain a satisfactory color and tonal balance as photographic images fade on exposure to light, it is important to achieve a balanced rate of density loss from yellow, magenta and cyan dyes. It is particularly desirable to produce a balanced rate of yellow and magenta dye loss in order to maintain a pleasing reproduction of skin tones. In accordance with preferred embodiments of the invention, a balanced rate of fade can be achieved using a yellow dye-forming layer comprising a stabilizer combination in accordance with preferred embodiments of this invention in combination with a magenta dye-forming coupler layer comprising highly-stable pyrazolotriazole coupler.
The yellow, cyan and magenta dye forming couplers that may be used in the elements of the invention can be defined as being 4-equivalent or 2-equivalent depending on the number of atoms of Ag+ required to form one molecule of dye. A 4-equivalent coupler can generally be converted into a 2-equivalent coupler by replacing a hydrogen at the coupling site with a different coupling-off group. Coupling-off groups are well known in the art. Such groups can modify the reactivity of the coupler. Such groups can advantageously affect the layer in which the coupler is coated, or other layers in the photographic recording material, by performing, after release from the coupler, functions such as dye formation, dye hue adjustment, development acceleration or inhibition, bleach acceleration or inhibition, electron transfer facilitation, color correction and the like. Representative classes of such coupling-off groups include, for example, chloro, alkoxy, aryloxy, hetero-oxy, sulfonyloxy, acyloxy, acyl, heterocyclyl, sulfonamido, mercaptotetrazole, benzothiazole, alkylthio (such as mercapto propionic acid), arylthio, phosphonyloxy and arylazo. These coupling-off groups are described in the art, for example, in U.S. Pat. Nos. 2,455,169; 3,227,551; 3,432,521; 3,476,563; 3,617,291; 3,880,661; 4,052,212 and 4,134,766; and in U.K. Patents and published Application Nos. 1,466,728; 1,531,927; 1,533,039; 2,006,755A and 2,017,704A, the disclosures of which are incorporated herein by reference.
To control the migration of various components coated in a photographic layer, including couplers, it may be desirable to include a high molecular weight hydrophobe or xe2x80x9cballastxe2x80x9d group in the component molecule. Representative ballast groups include substituted or unsubstituted alkyl or aryl groups containing 8 to 40 carbon atoms. Representative substituents on such groups include alkyl, aryl, alkoxy, aryloxy, alkylthio, hydroxy, halogen, alkoxycarbonyl, aryloxcarbonyl, carboxy, acyl, acyloxy, amino, anilino, carbonamido (also known as acylamino), carbamoyl, alkylsulfonyl, arysulfonyl, sulfonamido, and sulfamoyl groups wherein the substituents typically contain 1 to 40 carbon atoms. Such substituents can also be further substituted. Alternatively, the molecule can be made immobile by attachment to polymeric backbone.
Photographic elements of this invention can have the structures and components shown on Research Disclosure, February 1995, Item 37038, pages 79-114. Research Disclosure is published by Kenneth Mason Publications, Ltd., Dudley Annex, 12a North Street, Emsworth, Hampshire P010 7DQ, ENGLAND. Specific elements can be those shown on pages 96-98 of this Research Disclosure item as Color Paper Elements 1 and 2, in which is employed in the yellow dye forming layers the stabilizer combinations of the present invention instead of the stabilizers shown there. A typical multicolor photographic element of this invention comprises a support bearing a cyan dye image-forming unit comprised of at least one red-sensitive silver halide emulsion layer having associated therewith at least one cyan dye-forming coupler, a magenta dye image-forming unit comprising at least one green-sensitive silver halide emulsion layer having associated therewith at least one magenta dye-forming coupler, and a yellow dye image-forming unit comprising at least one blue-sensitive silver halide emulsion layer having associated therewith at least one yellow dye-forming coupler. The element can contain additional layers, such as filter layers, interlayers, overcoat layers, subbing layers, and the like. All of these can be coated on a support which can be transparent or reflective (for example, a paper support). Photographic elements of the present invention may also usefully include a magnetic recording material as described in Research Disclosure, Item 34390, November 1992, or a transparent magnetic recording layer such as a layer containing magnetic particles on the underside of a transparent support as in U.S. Pat. Nos. 4,279,945 and 4,302,523. The element typically will have a total thickness (excluding the support) of from 5 to 30 microns. While the order of the color sensitive layers can be varied, they will normally be red-sensitive, green-sensitive and blue-sensitive, in that order on a transparent support, (that is, blue sensitive furthest from the support) and the reverse order on a reflective support being typical.
This invention also contemplates the use of photographic elements of the present invention in what are often referred to as single use cameras (or xe2x80x9cfilm with lensxe2x80x9d units). These cameras are sold with film preloaded in them and the entire camera is returned to a processor with the exposed film remaining inside the camera. Such cameras may have glass or plastic lenses through which the photographic element is exposed.
In the following discussion of suitable materials for use in elements of this invention, reference will be made to Research Disclosure, September 1994, Number 365, Item 36544, which will be identified hereafter by the term xe2x80x9cResearch Disclosure I.xe2x80x9d The Sections hereafter referred to are Sections of the Research Disclosure I.
The silver halide emulsions employed in the elements of this invention can be either negative-working, such as surface-sensitive emulsions or unfogged internal latent image forming emulsions, or direct positive emulsions of the unfogged, internal latent image forming type which are positive working when development is conducted with uniform light exposure or in the presence of a nucleating agent. Suitable emulsions and their preparation as well as methods of chemical and spectral sensitization are described in Sections I through V. Color materials and development modifiers are described in Sections V through XX. Vehicles which can be used in the elements of the present invention are described in Section II, and various additives such as brighteners, antifoggants, stabilizers, light absorbing and scattering materials, hardeners, coating aids, plasticizers, lubricants and matting agents are described, for example, in Sections VI through X and XI through XIV. Manufacturing methods are described in all of the sections, other layers and supports in Sections XI and XIV, processing methods and agents in Sections XIX and XX, and exposure alternatives in Section XVI.
With negative working silver halide a negative image can be formed. Optionally a positive (or reversal) image can be formed although a negative image is typically first formed.
The photographic elements of the present invention may also use colored couplers (e.g. to adjust levels of interlayer correction) and masking couplers such as those described in EP 213 490; Japanese Published Application 58-172,647; U.S. Pat. No. 2,983,608; German Application DE 2,706,117; U.K. Patent 1,530,272; Japanese Application A-113935; U.S. Pat. No. 4,070,191 and German Application DE 2,643,965. The masking couplers may be shifted or blocked.
The photographic elements may also contain materials that accelerate or otherwise modify the processing steps of bleaching or fixing to improve the quality of the image. Bleach accelerators described in EP 193 389; EP 301 477; U.S. Pat. Nos. 4,163,669; 4,865,956; and 4,923,784 are particularly useful. Also contemplated is the use of nucleating agents, development accelerators or their precursors (UK Patent 2,097,140; U.K. Patent 2,131,188); electron transfer agents (U.S. Pat. Nos. 4,859,578; 4,912,025); antifogging and anti color-mixing agents such as derivatives of hydroquinones, aminophenols, amines, gallic acid; catechol; ascorbic acid; hydrazides; sulfonamidophenols; and non color-forming couplers.
The elements may also contain filter dye layers comprising colloidal silver sol or yellow and/or magenta filter dyes and/or antihalation dyes (particularly in an undercoat beneath all light sensitive layers or in the side of the support opposite that on which all light sensitive layers are located) either as oil-in-water dispersions, latex dispersions or as solid particle dispersions. Additionally, they may be used with xe2x80x9csmearingxe2x80x9d couplers (e.g. as described in U.S. Pat. No. 4,366,237; EP 096 570; U.S. Pat. Nos. 4,420,556; and 4,543,323.) Also, the couplers may be blocked or coated in protected form as described, for example, in Japanese Application 61/258,249 or U.S. Pat. No. 5,019,492.
The photographic elements may further contain other image-modifying compounds such as developer inhibitor releasing compounds (DIR""s).
The elements of the present invention may be employed to obtain reflection color prints as described in Research Disclosure, November 1979, Item 18716, incorporated herein by reference. The emulsions and materials to form elements of the present invention, may be coated on pH adjusted support as described in U.S. 4,917,994; with epoxy solvents (EP 0 164 961); with additional stabilizers (as described, for example, in U.S. Pat. Nos. 4,346,165; 4,540,653 and 4,906,559); with ballasted chelating agents such as those in U.S. Pat. No. 4,994,359 to reduce sensitivity to polyvalent cations such as calcium; and with stain reducing compounds such as described in U.S. Pat. Nos. 5,068,171 and 5,096,805. Other compounds useful in the elements of the invention are disclosed in Japanese Published Patent Applications 83/09,959; 83/62,586; 90/072,629, 90/072,630; 90/072,632; 90/072,633; 90/072,634; 90/077,822; 90/078,229; 90/078,230; 90/079,336; 90/079,338; 90/079,690; 90/079,691; 90/080,487; 90/080,489; 90/080,490; 90/080,491; 90/080,492; 90/080,494; 90/085,928; 90/086,669; 90/086,670; 90/087,361; 90/087,362; 90/087,363; 90/087,364; 90/088,096; 90/088,097; 90/093,662; 90/093,663; 90/093,664; 90/093,665; 90/093,666; 90/093,668; 90/094,055; 90/094,056; 90/101,937; 90/103,409; 90/151,577.
The silver halide emulsion grains to be used in the invention may be prepared according to methods known in the art, such as those described in Research Disclosure I and James, The Theory of the Photographic Process. These include methods such as ammoniacal emulsion making, neutral or acidic emulsion making, and others known in the art. These methods generally involve mixing a water soluble silver salt with a water soluble halide salt in the presence of a protective colloid, and controlling the temperature, pAg, pH values, etc, at suitable values during formation of the silver halide by precipitation.
The silver halide to be used in the invention may be advantageously subjected to chemical sensitization with noble metal (for example, gold) sensitizers, middle chalcogen (for example, sulfur) sensitizers, reduction sensitizers and others known in the art. Compounds and techniques useful for chemical sensitization of silver halide are known in the art and described in Research Disclosure I and the references cited therein.
The photographic elements of the present invention, as is typical, provide the silver halide in the form of an emulsion. Photographic emulsions generally include a vehicle for coating the emulsion as a layer of a photographic element. Useful vehicles include both naturally occurring substances such as proteins, protein derivatives, cellulose derivatives (e.g., cellulose esters), gelatin (e.g., alkali-treated gelatin such as cattle bone or hide gelatin, or acid treated gelatin such as pigskin gelatin), gelatin derivatives (e.g., acetylated gelatin, phthalated gelatin, and the like), and others as described in Research Disclosure I. Also useful as vehicles or vehicle extenders are hydrophilic water-permeable colloids. These include synthetic polymeric peptizers, carriers, and/or binders such as poly(vinyl alcohol), poly(vinyl lactams), acrylamide polymers, polyvinyl acetals, polymers of alkyl and sulfoalkyl acrylates and methacrylates, hydrolyzed polyvinyl acetates, polyamides, polyvinyl pyridine, methacrylamide copolymers, and the like, as described in Research Disclosure I. The vehicle can be present in the emulsion in any amount useful in photographic emulsions. The emulsion can also include any of the addenda known to be useful in photographic emulsions. These include chemical sensitizers, such as active gelatin, sulfur, selenium, tellurium, gold, platinum, palladium, iridium, osmium, rhenium, phosphorous, or combinations thereof. Chemical sensitization is generally carried out at pAg levels of from 5 to 10, pH levels of from 5 to 8, and temperatures of from 30 to 80xc2x0 C., as illustrated in Research Disclosure, June 1975, item 13452 and U.S. Pat. No. 3,772,031.
The silver halide may be sensitized by sensitizing dyes by any method known in the art, such as described in Research Disclosure I. The dye may be added to an emulsion of the silver halide grains and a hydrophilic colloid at any time prior to (e.g., during or after chemical sensitization) or simultaneous with the coating of the emulsion on a photographic element. The dye/silver halide emulsion may be mixed with a dispersion of color image-forming coupler immediately before coating or in advance of coating (for example, 2 hours).
Photographic elements of the present invention are preferably imagewise exposed using any of the known techniques, including those described in Research Disclosure I, section XVI. This typically involves exposure to light in the visible region of the spectrum, and typically such exposure is of a live image through a lens, although exposure can also be exposure to a stored image (such as a computer stored image) by means of light emitting devices (such as light emitting diodes, CRT and the like).
Photographic elements comprising the composition of the invention can be processed in any of a number of well-known photographic processes utilizing any of a number of well-known processing compositions, described, for example, in Research Disclosure I, or in T. H. James, editor, The Theory of the Photographic Process, 4th Edition, Macmillan, N.Y., 1977. In the case of processing a negative working element, the element is treated with a color developer (that is one which will form the colored image dyes with the color couplers), and then with a oxidizer and a solvent to remove silver and silver halide. In the case of processing a reversal color element, the element is first treated with a black and white developer (that is, a developer which does not form colored dyes with the coupler compounds) followed by a treatment to fog unexposed silver halide (usually chemical or light fogging), followed by treatment with a color developer. Preferred color developing agents are p-phenylenediamines. Especially preferred are: 4-amino-N,N-diethylaniline hydrochloride, 4-amino-3-methyl-N,N-diethylaniline hydrochloride, 4-amino-3-methyl-N-ethyl-N-(b-(methanesulfonamido)ethylaniline sesquisulfate hydrate, 4-amino-3-methyl-N-ethyl-N-(b-hydroxyethyl)aniline sulfate, 4-amino-3-b-(methanesulfonamido)ethyl-N,N-diethylaniline hydrochloride and 4-amino-N-ethyl-N-(2-methoxyethyl)-m-toluidine di-p-toluene sulfonic acid.
Development is followed by bleach-fixing, to remove silver or silver halide, washing and drying. Bleaching and fixing can be performed with any of the materials known to be used for that purpose. Bleach baths generally comprise an aqueous solution of an oxidizing agent such as water soluble salts and complexes of iron (III)(e.g., potassium ferricyanide, ferric chloride, ammonium or potassium salts of ferric ethylenediaminetetraacetic acid), water-soluble persulfates (e.g., potassium, sodium, or ammonium persulfate), water-soluble dichromates (e.g., potassium, sodium, and lithium dichromate), and the like. Fixing baths generally comprise an aqueous solution of compounds that form soluble salts with silver ions, such as sodium thiosulfate, ammonium thiosulfate, potassium thiocyanate, sodium thiocyanate, thiourea, and the like.
The photographic elements comprising stabilizers in accordance with this invention may be processed in amplification processes that use developer/amplifier solutions described in U.S. Pat. No. 5,324,624, for example. When processed in this way, the low volume, thin tank processing system and apparatus described in U.S. Pat. No. 5,436,118 preferably is employed.